1. Field of the Invention
The invention pertains to a hygienic evacuation valve, typically employed in food industry, pharmaceutical or medical processing equipment. The novel hygienic evacuation valve includes a first piston cylinder combination for positively opening and closing a vacuum source which is ported in the housing to an evacuation port in combination with a second piston cylinder combination for rapidly releasing the vacuum after the packaging machine has sealed the product. Optionally, a special gassing or sterilization port may be providing along with a positive pressure release to assist in the release of the sealed package. The optional special gassing or the provision for a sterilized environment for the packaged product can be provided by a gassing port associated with the housing of the novel hygienic evacuation valve.
The novel hygienic evacuation valve includes a housing with a first piston having a sealing head for sealing a vacuum fitting having a tapered seat for receiving the sealing head of the first piston and a second piston, the second piston also having a sealing head for seating in a tapered seat in the novel evacuation valve in which the first piston and second piston are pneumatically controlled to operate sequentially to first close the vent port and then open the vacuum inlet to the vacuum outlet of the housing to provide evacuation of a product on a product processing machine and then, once evacuated, close the first piston and open the second piston to rapidly release the vacuum in the valve and the line to the product processing machine after sealing of the product. The rapid release of vacuum from the valve and the line to the packaged product as well as the option to provide positive pressure after closing the vacuum line assists in removing the sealed product from the product processing machine.
The novel evacuation valve further includes ports for providing special gas environments or the sterilization of packaged products by the introduction of specialized gasses into the product to be packaged to provide either a sterilized or a special gas environment for the packaged product. After providing a special gas environment or sterilization the vent port valve piston is closed and the evacuation piston is opened to remove some, if not all, the special gas from the inside of the package prior to sealing and then reopening the vent port valve piston to rapidly remove vacuum pressure to assist in the separation of the sealed and packaged product. In the preferred application of the novel evacuation valve, the wall or walls of the packaged product are collapsed around the package as is common in the vacuum packaging of cheese and dairy products in sealed thin film plastic packages.
Optionally, the novel evacuation valve may be adapted and operated to first evacuate a product to be packaged by first closing the vent port valve, then opening the evacuation piston to evacuate the package and then opening the special sterilization or gassing port to admit a special sterilization or processing gas to the package before sealing the package. Once the package is sealed the vent port is opened to release the vacuum in the line to the packaged product. In such applications, the packaged product is generally placed in sealed containers Which have one or more non-deformable walls such as are utilized in the packaging of cheese, meats and the packaging of some medical devices.
The novel evacuation valve includes flanges for connecting the vacuum inlet fitting to the housing, as well as a flange for connecting the vacuum outlet to the product processing machine and a further flange for connecting the first cylinder housing to the evacuation valve. An optional fourth flange can be provided for connecting the vent valve or gassing ports to the novel hygienic evacuation valve housing. The purpose of utilizing flanges in the preferred application of the invention is to provide a seamless, non-threaded, smooth stainless steel valve for processing packaged products requiring a clean, hygienic, sterile or sanitary environment.
The novel method of the invention provides for the hygienic and sanitary packaging of products requiring a partially or substantially completely evacuated package or a package containing a specialized gassed, sterilized or treated ambient environment prior to the sealing of the packaged product. The method provides for the treatment of the product in the package by the introduction of various sterilizing fluids or specialized gasses into the product before the sealing of the product package before the sealing of the package and subsequent release of the vacuum to the packaged product and release of the packaged and sealed product from the processing machine.
The advantages of the novel evacuation valve and method include the ability to place the novel hygienic evacuation valve in situ on the package processing machine as a result of the compact size of the novel evacuation valve. The novel evacuation valve further allows a single port to the packaged product to accomplish a multiplicity of functions including gassing, evacuating and venting in a single line as opposed to the requirement in the prior art of multiple lines to the packaged product. Further the novel evacuation valve positively opens and closes the vacuum and positively controls ventilation by the utilization of the first and second pistons and eliminates the necessity of remotely mounting the valve with respect to the processing machine and requiring the inefficient application of vacuum to the packaging machine by requiring vacuum hoses and a multiplicity of other hoses to run from the remotely located vacuum valve to the packaging machine.
2. Description of Related Art, Including Information Disclosed Under 37 C,F.R, 1.97 and 1.98
The prior art includes various types of vacuum valves employed in a variety of different machines and packaging applications. A few of the vacuum valves include various types of ports and systems for relieving vacuum pressure once the vacuum has been removed from the source. Some of these valves include threads and various types of vacuum fittings, which are generally not compatible with applications involving medical, pharmaceutical and food processing applications, which require an evacuation valve without seams or threads in which food or processed products can collect to contaminate the contents of the sanitary packaged material. Hygienic evacuation valves typically used in the food processing art, are commonly remotely located from the food processing machine as a result of their size and the complexity of their components. Typically, such remotely located valves require the connection of long vacuum hoses from the remotely located valve to the packaging machine, which reduces the efficiency of the evacuation process.
Further, such vacuum valves, due to their size and complexity, require an amount of space that is incompatible with locating the valve on the product processing and packaging machines. Typical prior art vacuum valves used in the food processing and pharmaceutical processing industries for hygienically packaging food products includes the Tiament valve manufactured by the Tiament Company at Im Rutter in D-35216 Biedenkopf Wallau, Germany. This valve is typically remotely located in a housing separate from the packaging machine and typically takes up a space of about 12 inches by 6 inches and includes hoses that connect the valve to the hygienic packaging machine.
Unlike available evacuation valves used in the food processing industry, the present valve is of a compact design, employs a positive control over both the vacuum inlet piston and vacuum vent piston and can be disposed directly on the hygienic packaging machinery. Further, unlike the available prior art the novel evacuation valve is designed to utilize a single port to not only evacuate but also to gas-purge and release pressure in the line, valve housing and port. In addition as a result of its compact size the novel valve allows the more efficient utilization of vacuum along with the more positive control over the vacuum, utilizing pistons having a cylindrical sealing head, in combination with a frustro-conical or tapered valve seat to positively control the opening and closing of the vacuum, as well as the opening and closing of the venting ports.
Other prior art uncovered in a patent search, includes Woods U.S. Pat. No. 4,221,101, which illustrates generally the type of packaging machines and processes utilized for sealing a food product such as cheese and bacon. As illustrated in FIG. 7, a pair of tubes are employed to provide for gassing and evacuation from a remotely located evacuation valve. The invention, unlike the prior art, allows the novel evacuation valve to be disposed in situ on the packaging machine as a result of its compact size and utilizes a single tube to provide evacuation, gassing and the release of pressure in the tube and valve housing.
Prior art valves uncovered in the search also include xe2x80x9ctwo-in-onexe2x80x9d pressure and vacuum relief vent devices as represented by Zenkich U.S. Pat. No. 5,479,978. These prior art valves, like the novel evacuation valve of the invention, utilize a single port in the container wall to supply vacuum and pressure release. Unlike the present invention, such prior art does not provide positive control over both vacuum and pressure relief, provide three in one capabilities and are not designed for medical pharmaceutical and food processing applications.
Beck U.S. Pat. No. 5,564,457 provides a vacuum breaker valve configured for clean in place applications in the food and dairy processing industry. The vacuum breaker valve of Beck U.S. Pat. No. 5,564,457 is, however, not used for vacuum packaging, but instead provides for the entry of air into the valve body upon the depressurization of fluid to prevent a siphoning effect upon a fluid (liquid) in the passageway or conduit. The only features shared by Beck U.S. Pat. No. 5,564,457 and the invention are the ease of cleaning the valve and the valve""s application to the food processing industry.
The invention pertains to a novel evacuation valve for use in pharmaceutical, medical and food processing applications having a single outlet port for gassing, evacuation and pressure release utilizing positive control over a first piston or vacuum, piston for opening and closing a vacuum port to a packaged product and positive control over a second piston or vent piston after the packaging or sealing of the package to rapidly release the vacuum to assist in the rapid release of an evacuated and sealed package from the packaging machine.
The novel compact evacuation valve eliminates problems of prior art packaging valves by providing a seamless, non-threaded valve assembly preferably made of stainless steel or other materials and alloys suitable for the sterile and hygienic handling of food, medical and pharmaceutical materials. The novel evacuation valve assembly includes a main valve body or housing, a piston activating chamber and a vacuum inlet assembly which are connected together with flange clamps. The utilization of flange clamps assists in the cleaning and maintenance of the valve in a sanitary and hygienic condition and allows for easy removal, cleaning and sterilization of the components.
As a consequence of its compact design, the novel valve not only can be attached in situ or directly on the packaging and filling machines, but also, the novel evacuation valve utilizes vacuum more efficiently allowing orifice sizes to be reduced as much as ⅓ the size of orifices on comparable vacuum valves. The compact nature of the design, as well as its positive control over vacuum and venting and optional specialized gassing or sterilization processing of packages allows the novel evacuation valve to be utilized in accordance with the method of the invention, which provides for attaching the novel valve directly to the product packaging machine, instead of requiring remote location of the novel evacuation valve, as has heretofore been utilized in the prior art.
The novel evacuation valve includes a main housing for accommodating a first piston having a sealing head for positively opening and closing a vacuum inlet connected to a vacuum outlet port in the housing. A second piston, disposed intermediate the vacuum outlet and a vent valve, operates to open and close the vent to the vacuum outlet. The operation of the first piston and the second piston to open and close the vacuum and vent ports are controlled by a solenoid. In operation, when the first piston is closed, the second piston opens the vent to the vacuum outlet and when the first piston is open the second piston closes the vent. The first and second pistons, preferably include a sealing head designed to seat in a tapered opening to provide positive control over vacuum and venting operations.
The first and second pistons are preferably pneumatically operated, which, together with the shape of the piston sealing head, in combination with the tapered seats, provide a rapid and positive control over the vacuum and venting operations. The positive control over vacuum, venting and gassing is provided by utilizing a piston with a tapered seat. This arrangement is further augmented by disposing the tapered seat intermediate the piston sealing head and the housing with the tapered seat tapering toward the area of greatest vacuum or least pressure.
An optional product gassing or sterilization processing port is provided in the valve housing to gas or provide for the sterilization of the product in the package before it is sealed. The optional gassing or sterilization port can also be opened and closed with a pneumatically controlled piston. Typically in food and pharmaceutical industries, a gas is introduced into the product package before the product is evacuated and sealed. The novel processing port can introduce nitrogen as is typically used in the food processing industry, or an inert gas or other processing or sterilization gas into the packaged product. Once gassing is complete the vent port is closed, the evacuation port opened by the activation of the vacuum piston to remove excess nitrogen, inert gas, or other processing gas introduced into the packaged product. Upon completion of evacuation, the first piston or vacuum piston is closed and the venting piston or second piston is opened. Optionally, the venting piston can be connected either to the ambient environment or to a positive pressure source to provide a positive pressure for assisting in the release of the sealed packaged product.
The novel evacuation valve of the invention, as a result of its compact size and configuration, is easily cleaned on the machine, easily disassembled for maintenance or sterillzation for use in various pharmaceutical, medical and food and dairy products applications.